ADF (ArcInfo Binary Grid Format)
Dec 3,2025

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Introduction

ADF (ArcInfo Binary Grid Format) is a proprietary raster data format developed by Esri. It is used for storing and managing raster data, which can contain various types of geospatial information such as elevation data, land cover types, vegetation indices, etc. The ADF format can store raster layers with different resolutions and data types, making it significant in GIS applications.

File Structure

The ADF (ArcInfo Binary Grid) file structure consists of multiple key components, which together form a complete raster dataset. The specific structure is as follows:

hdr.adf (Header File): Stores basic metadata of the raster data, including tile size, number of tiles, data type (e.g., 4-byte integer or floating-point), number of rows and columns, etc.
w001001.adf (Raster Data File): Stores raster pixel values in a tiled/blocked format using run-length encoding compression to reduce storage space.
dblbnd.adf (Boundary Information File): Defines the geographic boundary of the raster data, storing coordinates of the four corners (LLX, LLY, URX, URY), representing the lower-left, upper-left, lower-right, and upper-right longitude/latitude or projected coordinates, ensuring correct spatial positioning of the data.
sta.adf (Statistical Information File): Contains statistical summaries of the raster data, such as minimum, maximum, mean, standard deviation, etc., used for quickly understanding data distribution characteristics and supporting subsequent statistical calculations.
vat.adf (Value Attribute Table File): For classified raster data (e.g., land use types), stores attribute information corresponding to each unique value (e.g., category name, color code, etc.).
prj.adf (Projection Definition File): An optional file that stores coordinate system information of the raster data (e.g., WGS84, UTM, etc.) in ESRI standard format, ensuring spatial alignment with other geographic layers. If missing, projection information may need to be retrieved from the accompanying info folder or external metadata.
info folder (Accompanying Directory): An info directory at the same level as the ADF folder contains associated attribute tables (e.g., polygon boundaries, annotation labels, etc.).

Pros

Native support for geospatial operations: ADF is specifically designed for ArcGIS/ArcInfo and seamlessly integrates with the ESRI software ecosystem. It can be directly used for spatial analysis (e.g., overlay analysis, distance calculations) and terrain modeling (e.g., slope/aspect analysis) without format conversion, reducing the risk of data loss.
Efficient tiled storage and compression: Uses a tiled storage structure to divide large rasters into smaller blocks (e.g., w001001.adf), combined with run-length encoding compression, significantly reducing storage space. This is particularly suitable for storing continuous data (e.g., elevation, temperature).
Comprehensive metadata support: Key information such as data type, number of rows and columns, and tile size is stored in the hdr.adf (header file), while geographic boundaries and coordinate systems are defined in dblbnd.adf (boundary file) and prj.adf (projection file), ensuring data accuracy and traceability in spatial analysis.
Attribute association for classified data: The vat.adf (value attribute table) allows attaching attribute information (e.g., names, color codes) to each unique value (e.g., land use categories), enabling mapping from numerical values to semantics, facilitating visualization and querying of classified data.
Historical compatibility and stability: As a classic ESRI format, ADF was widely used in early GIS projects. Many legacy datasets are still stored in this format, and its stable structure makes it suitable for long-term archiving without easy corruption.

Cons

Native support for geospatial operations: ADF is specifically designed for ArcGIS/ArcInfo and seamlessly integrates with the ESRI software ecosystem. It can be directly used for spatial analysis (e.g., overlay analysis, distance calculations) and terrain modeling (e.g., slope/aspect analysis) without format conversion, reducing the risk of data loss.
Efficient tiled storage and compression: Uses a tiled storage structure to divide large rasters into smaller blocks (e.g., w001001.adf), combined with run-length encoding compression, significantly reducing storage space. This is particularly suitable for storing continuous data (e.g., elevation, temperature).
Comprehensive metadata support: Key information such as data type, number of rows and columns, and tile size is stored in the hdr.adf (header file), while geographic boundaries and coordinate systems are defined in dblbnd.adf (boundary file) and prj.adf (projection file), ensuring data accuracy and traceability in spatial analysis.
Attribute association for classified data: The vat.adf (value attribute table) allows attaching attribute information (e.g., names, color codes) to each unique value (e.g., land use categories), enabling mapping from numerical values to semantics, facilitating visualization and querying of classified data.
Historical compatibility and stability: As a classic ESRI format, ADF was widely used in early GIS projects. Many legacy datasets are still stored in this format, and its stable structure makes it suitable for long-term archiving without easy corruption.

Application Scenario

The ADF (ArcInfo Binary Grid) format is primarily used in early or specific ESRI ecosystem scenarios for geospatial data processing. For example, it efficiently stores and manages continuous raster data (e.g., elevation models, soil moisture) in ArcGIS software, supporting basic spatial operations such as terrain analysis and slope calculations. Its tiled compression structure is suitable for handling large-scale datasets, while its value attribute table (VAT) enables semantic association of classified data (e.g., land use types), making it useful for thematic mapping in fields like environmental monitoring and urban planning. Despite limited cross-platform compatibility, ADF remains a stable format for legacy project maintenance, data archiving, or internal ESRI exchanges, particularly in geospatial engineering projects requiring long-term preservation and reliance on the ArcGIS ecosystem.